Rockwell Automation 1336T FORCE Series B - Manual (Page 253)

Appendix A
A–5
Cable Termination Optional Cable Terminator
Voltage doubling at motor terminals, known as reflected wave
phenomenon, standing wave or transmission line effect, can occur when
using drives with long motor cables.
Inverter duty motors with phase–to–phase insulation ratings of 1600 volts
or higher should be used to minimize effects of reflected wave on motor
insulation life.
Applications with non–inverter duty motors or any motor with
exceptionally long leads may require an output inductor or cable
terminator. An inductor or terminator will help limit reflection to the
motor, to levels which are less than the motor insulation value.
Tables 2.A & 2.B list the maximum recommended cable length for
unterminated cables, since the voltage doubling phenomenon occurs at
different lengths for different drive ratings. If your installation requires
longer motor cable lengths, a reactor or cable terminator is recommended.
Optional Output Reactor
The reactors listed in the 1336 FORCE price list can be used for drive input
and output. These reactors are specifically constructed to accomodate
IGBT inverter applications with switching frequencies up to 20 KHz. They
have a UL approved dielectric strength of 4000 volts, opposed to a normal
rating of 2500 volts. The first two and last two turns of each coil are triple
insulated to guard against insulation breakdown resulting from high dv/dt.
When using motor line reactors, it is recommended that the drive PWM
frequency be set to its lowest value to minimize losses in the reactors.
Important: By using an output reactor the effective motor voltage will be
lower because of the voltage drop across the reactors – this may also mean
a reduction of the motor torque.
Common Mode Cores – Common Mode cores will help reduce the
common mode noise at the drive output, and guard against tripping of the
drive caused by capacitive leakage effects. The capacitive currents are
larger at higher PWM frequencies.
Enclosures Customer Supplied Enclosure Requirements – 1336 FORCE drives
installed in customer supplied enclosures may be mounted within an
enclosure or may be mounted to allow the heatsink to extend outside the
enclosure. Use the information in Table A.3 in combination with the
enclosure manufacturer’s guidelines for sizing.